Means for forming threaded wire



July 5, 1966 c, To JR 3,258,949

MEANS FOR FORMING THREADED WIRE Original Filed Feb. 14, 1962 2Sheets-Sheet 1 619417465 D. 70AM); J70.

2 INVENTOR.

ATTORMCY July 5, 1966 '1 INVENTOR. mamas D. roman J'A.

Arm/mar United States Patent 3,258,949 MEANS FOR FORMING THREADED WIRECharles D. Toney, Jr., Atlanta, Ga., assignor to The Auto- SolerCompany, a corporation of Georgia Original application Feb. 14, 1962,Ser. No. 173,197. Divided and this application July 21, 1965, Ser. No.

Claims. (Cl. 72-103) This is a division of application Serial No.173,197, filed February 14, 1962, now abandoned, and is related tocopending application Serial No. 430,034, filed February 2, 1965, whichlatter application claims the product and process of the presentinvention and is a continuation of the aforesaid application Serial No.173,197.

The present invention relates generally to threaded wire andparticularly to a new and unique method and means for forming threadedwire in an expeditious and inexpensive manner.

The threaded wire produced by the present invention lends itself toadvantage particularly for use with fastener forming and insertingmachines in which wire is formed into fastener lengths and inserted intoobjects to hold them together; the threaded surface configurationenhancing straight driving and holding. strength characteristics of thefasteners formed and inserted by these machines. A representativeexample of such a fastener forming and inserting machine is illustratedand described in US. Patent No. 2,944,758, issued July 12, 1960.

Briefly described the threaded wire of the present invention is producedby impressing discontinuous segments of spiral, thread-like grooves atthe surface of a Wire to be threaded, while causing the impressions toprogress in a spaced sidewise succession about the wire in a spiralpath. Preferably the impressions are made in a pair of diametricallyopposed spiral paths with the pitch of the paths such that the pathscomplement each other in a generally contiguous alternation along thelength of the wire, which contiguity in combination with a generalspiral alignment of the groove segments of adjacent paths producessubstantially continuous thread-like spiral grooves around the wire.

Such impression of discontinuous groove segments at the surface of awire in a sidewise succession following a spiral path is obtainedaccording to the present invention with means characterized by acylindrical die having a die surface formed at a circumferentialconcavity with configuration forming segments extending across saidconcavity, which is shaped in relation to the configuration formingsegments such as to dispose the segments in a discontinuous segmentalforming array. This concave die surface provides extended contact withthe surface of a wire when the wire is seated diagonally in theconcavity. Also, the diagonal positioning of the wire with respect tothe concavity results in the die surface following a spiral path when itis rolled around the wire to impress the die configuration thereat. Apair of such dies arranged in diametrical opposition and at a properinclination will impress groove segments in the aforementioned pair ofcomplementary contiguous spiral paths with the segments of adjacentpaths being contiguous and cumulative.

To impress thread-like groove segments on the wire with these dies,their die surfaces are formed with spaced, parallel ridges that extendacross the concavity at an inclination thereto less than the inclinationof the diagonally seated wire so that the groove segments formed by theridges of the dies will extend across the discontinuous spiral paths ofimpression on the wire, thereby permitting arrangement of the grooves ofadjacent paths in alignment to form substantially continuous thread-likegrooves.

The above described concave die surface feature of the die of thepresent invention is particularly applicable to produce a threaded wire.

3,258,949 Patented July 5, 1966 the production of the threaded wire ofthe present invention using the method of the present invention.However, this concave die surface feature is applicable as well to theproduction of surface configurations other than threads or grooves.

Although the term threaded is used throughout the present specificationand claims it should be understood that this term is not intended to belimited to a strict interpretation as the thread of the presentinvention may be merely a simulated thread and need not have a trulyhelical configuration nor be truly continuous.

The features and advantages of the present invention will be apparentfrom the following description and accompanying drawings, in which:

FIG. 1 is a diagrammatic illustration of an apparatus for carrying outthe principles of the present invention with a pair of forming dies ofthe present invention;

FIG. 2 is a plan view of a forming die of the type illustrated in FIG. 1with an indication of the preferred diagonal position of a wire forproper die forming engagement of the wire by the die; and

FIG. 3 is a plan view of a length of threaded wire according to thepresent invention and illustrating the position of the forming dies forforming the threaded configuration in accordance with the presentinvention.

The present invention will now be described in relation to a preferredembodiment in which a surface forming die is used in a method ofspirally configurating wire to This threaded wire 10 has threads 12formed by spaced spiral grooves 14 with flat spiral surfaces 16therebetween. This threaded configuration provides particularlydesirable improved straight driving and holding strength characteristicsin fasteners formed from this wire.

The threaded wire 10, illustrated in substantial enlargement in FIG. 3,is produced according to a preferred embodiment of the present inventionusing the forming apparatus 20 illustrated in FIG. 1. This apparatus 20includes thread forming means 22 that impress a surface configuration onthe wire 10 as it is drawn through the apparatus 20.

The thread forming means 22 comprises a pair of die rolls 30 disposed indiametrical opposition with respect to the traveling wire 10. Theserolls 30 are each mounted for free rotation in a yoke 24 slidablysupported in a rotating assembly indicated diagrammatically at 28, andurged diametrically inwardly by suitable biasing means indicateddiagrammatically at 26, which may be in the form of a spring or a leverarm actuated by centrifugal force or any other suitable means. The yokes24, rotating assembly 28 and biasing means 26 constitute means formounting the die rolls 30 in operating relation.

The details of the assembly construction 28 do not form a part of thepresent invention and can be of any suitable conventional construction.This assembly 28 is mounted for rotation in the direction of the arcuatearrow in FIG. 1 and suitable drive means (not shown) are provided toimpart positive rotation to the assembly 28, thereby revolving the dierolls 30 around the wire 10 as the wire is drawn through the formingapparatus 20 with the diametrical opposition of .the rolls 30 and theurging of the biasing means 26 causing the wire 10 to be tightly clampedbetween the rolls 30 for impressing the surface configuration of therolls onto the surface of the wire. In addition, the yokes 24 areinclined to position the rolls 30 with their axes inclined to a planeperpendicular to the axis of the wire and with the rolls equallyinclined but in opposite directions so that as the wire is drawn throughthe forming apparatus 20 with the assembly 28 rotating the die rolls 30will progress around the surface of the Wire 10 in spiral paths. I

One of the die rolls 30 is shown in FIG. 2 substantially enlarged forclarity of detail. This roll 30 is seen to comprise a cylindrical body32; around the circumference of which there is formed an arcuateconcavity 34 having a die surface 36 of a desired configuration toproduce by impression the desired configuration at the surface of thewire. To produce the previously described threaded surface 12 on thewire the die surface 36 of the circumferential arcuate concavity 34 iscomposed of spaced substantially parallel ridges 38 with complementarygrooves 40 therebetween. These ridges 38 and associated grooves 4i)extend across the arcuate concavity 34 at an inclination with respect tothe axis of the die roll 39 with the result that the ridges 38 impressdiscontinuous groove segments 42 at the surface of the wire 10 thatextend across the paths of impression.

The circumferential arcuate concavity 34 is formed with a radius ofcurvature greater than the radius of the wire to be formed so that whenthe roll 30 is inclined with respect to the Wire as aforementionedduring the forming operation, the wire 10 will be seated in theconcavity with extended contact between the die surface 36 of theconcavity 34 and the surface of the wire 13. The concavities 34 areshaped in relation to the ridges 38 such as to dispose the ridges ofeach die roll 31) in a discontinuous segmental forming arraysubstantially fully across the concavity. In the preferred embodimentthe concavities 34 of the die rolls 30 are shaped in relation to thewire size and respective inclination to provide forming contactsubstantially fully across the width of the concavities 34, therebyforming discontinuous groove segments 42 at the surface of the wire 10in paths 44 and 46 (FIG. 3) of widths substantially equivalent to thewidth of the concavity 34.

,As the die roll 30 follows a spiral path 44 around the wire 10 theridges 38 make spiral contact with the wire surface and therefore formthe groove segments 42 in a spiral configuration. In order to form thegroove segments 42 so that they extend across the paths 44 and 46 in thesame spiral direction as the paths but at a greater pitch (the advancemeasured longitudinally along the wire of one complete spiralrevolution) than the path, the ridges 38 of the die surface concavity 34are inclined to the circumferential center line of the concavity at anangle less than the corresponding inclination of the inclined ordiagonal position of the wire 10.

With a pair of rolls 3!) operating in the forming apparatus 20 of FIG.1, the wire is formed with two diametrically opposed paths 44-, 46 (FIG.3) with the angle of inclination of the rolls and the width of thepath-forming concavity being related to form the paths 44 and 46 insubstantial contiguity with the individual revolutions of the pathsbeing disposed in adjacent contiguous alternation along the length ofthe wire 10. The location of the contiguous edges of the paths 44 and 46is indicated by the dash lines 43 in FIG. 3. The location of the rollswith respect to the wire to form these paths is seen in dotdash lines inFIG. 3 with the front roll indicated as 39 and the back roll indicatedas 30b.

In the preferred embodiment, the grooved segments 42 of adjacent paths44, 46 are generally spirally aligned in cumulative relation to producesubstantially continuous thread-like grooves across the paths along theentire length of the wire 10. This alignment is accomplished by formingthe die rolls 30 with identical die surfaces 36 so that the ridges 38have the same pitch on each die. As these dies progress around thesurface of the wire the ridges 38 on each die tend to align themselveswith the adjacent groove segments 42 in the contiguous path formed bythe opposite die. To continue this general spiral alignment throughoutthe length of the wire, the groove segments 42 in succeeding revolutionsof the same path should be spaced with relation to the lengths of thespiral path revolutions so that there is general spiral alignment ofgrooves in succeeding revolutions of each path as well as alignment ofgrooves in adjacent revolutions of the different paths.

However, it is not necessary that precise alignment be obtained inadjacent revolutions of the different paths and in succeedingrevolutions of the same paths. Thus the alignment shown in FIG. 3 mayvar due, for example, to slight misalignment or slight skew of thecurvature imparted at the ends of the ridges 38. A general spiralalignment is all that is desired in the threaded configuration for mostpurposes.

The depth and width of the grooves 14 and therefore the width of theflat surfaces 16 are dependent upon the degree of impression of theridges 38 of the die surfaces 36 of the rolls 39. If the force of thebiasing means 26 is increased, the degree of impression of the ridges 38will thereby increase the depth and width of the formed grooves 14 anddecrease the width of the intermediate flat surfaces 16.

In the embodiment illustrated, the spiral thread-like grooves areproduced with the dies 39 inclined at an angle of 35 degrees withrespect to the length of the diagonally seated wire, with thediametrically opposed rolls being oppositely inclined at the same angleto produce spiral paths inclined at this same 35 angle. The ridges 38 onthe die surfaces 36 of the rolls 30 are formed at an inclination of 25to the circumferential center of the die, thereby producing a 10inclination of the ridges with respect to the Wire, which ridges impressgrooves 4% on the wire 10 at this same 10 angle.

The present invention has been described in detail above for purposes ofillustration only and is not intended to be limited by this descriptionor otherwise except as defined in the appended claims.

I claim:

1. A surface forming die comprising a cylindrical body having a diesurface formed at a circumferential arcuate concavity of a radius ofcurvature greater than the radius of a cylindrical object to be formedand having configuration forming segments extending across saidconcavity, said concavity being shaped in relation to said configurationforming segments such as to dispose said segments in a discontinuoussegmental forming array substantially fully across said concavity, saidbody being adapted for rolling diagonally around the length of materialto impress the discontinuous configuration segments in a spiral pat 2. Adie for impressing a spiral configuration on a length of wire comprisinga cylindrical body having a circumferential arcuate concavity of aradius of curvature greater than the radius of the length of wire andwith a die surface thereat formed by spaced ridges extending across theconcavity, said concavity being shaped in relation to said spaced ridgessuch as to dispose said ridges in a discontinuous segmental formingarray substantially fully across said concavity when the wire is seateddiagonally in the concavity, said body being adapted for rollingdiagonally around the wire to impress said ridges into formingengagement with the surface of the wire and thereby form thereat aplurality of discontinuous segments of grooves in spaced sidewisesuccession in a spiral path.

3. Means for impressing a desired surface configuration on a length ofwire comprising at least two dies, each of said dies having acylindrical body and a die surface formed at a circumferential arcuateconcavity of a radius of curvature greater than the radius of the lengthof wire with configuration forming segments extending across saidconcavity, said concavity being shaped in relation to said configurationforming segments such as to dispose said segments in a discontinuoussegmental forming array substantially fully across said concavity, meansfor mounting said dies for rolling in equally spaced circumferentialrelation around the length of wire with the dies inclined with respectto the wire to cause the rolling of said dies to progress about the wirein adjacent spiral paths and to provide seating of the wire diagonallyin the die concavities for extended contact of the wire across theconcavities such that each die impresses discontinuous configurationsegments on the wire with the discontinuous segmentsof adjacent pathsbeing cumulative.

4. Means for impressing a desired surface configuration on a length ofwire comprising a pair of dies having cylindrical bodies with diesurfaces formed at circumferential arcuate concavities withconfiguration forming segments extending across said concavities, theradius of curvature of each of said concavities being greater than theradius of the length of wire, said concavities being shaped in relationto said configuration forming segments such as to dispose said segmentsin each concavity in a discontinuous segmental forming array, means formounting said dies for rolling in diametrically opposed relation aroundthe length of Wire with the dies inclined with respect to the wire toseat the wire diagonally in the concavities such that said dies impressdiscontinuous configuration segments on the wire in adjacent contiguousspiral paths with the discontinuous segments of adjacent paths beingcontiguous and cumulative.

5. Means for impressing a desired surface configuration on a length ofWire according to claim 4 and charac terized further in that saidconfiguration forming segments are in the form of spaced ridgesextending said concavities at a lesser inclination to thecircumferential direction of the concavities than the inclination of thediagonally seated wire and proportioned to impress discontinuous groovesegments at the surface of the wire With the discontinuous groovesegments in one path in generally spiral alignment with thediscontinuous groove segments in the other path.

References Cited by the Examiner UNITED STATES PATENTS 2,720,801 10/1955Erdelyi et a1 72-403 CHARLES W. LANHAM, Primary Examiner.

J. D. HOINKES, Assistant Examiner.

1. A SURFACE FORMING DIE COMPRISING A CYLINDRICAL BODY HAVING A DIESURFACE FORMED AT A CIRCUMFERENTIAL ARCUATE CONCAVITY OF A RADIUS OFCURVATURE GREATER THAN THE RADIUS OF A CYLINDRICAL OBJECT TO BE FORMEDAND HAVING CONFIGURATION FORMING SEGMENTS EXTENDING ACROSS SAIDCONCAVITY, SAID CONCAVITY BEING SHAPED IN RELATION TO SAID CONFIGURATIONFORMING SEGMENTS SUCH AS TO DISPOSED SAID SEGMENTS IN A DISCONTINUOUSSEGMENTAL FORMING ARRAY SUBSTANTIALLY FULLY ACROSS SAID CONCAVITY, SAIDBODY BEING ADAPTED FOR ROLLING DIAGONALLY AROUND THE LENGTH OF MATERIALTO IM-